As technology continues to advance and the demand for video and audio signal processing continues to increase at a rapid rate, effective and efficient techniques for signal processing and data transmission have become more and more important in system design and implementation. Various standards or specifications for multimedia processing and transmission including video signal processing have been developed over the years to standardize and facilitate various coding schemes relating to multimedia signal processing. In particular, a group known as the Moving Pictures Expert Group (MPEG) was established to develop a standard or specification for the coded representation of moving pictures and associated audio stored on digital storage media. As a result, a standard known as the ISO/IEC 14496-2 (Part 2—Visual) CODING OF AUDIO-VISUAL OBJECTS (also referred to as the MPEG-4 standard or MPEG-4 specification herein), published December, 1999, was developed which standardizes various coding schemes for visual objects or video signals. ISO stands for International Organization for Standardization and IEC stands for International Electrotechnical Commission, respectively. Generally, the MPEG specification does not standardize the encoder but rather the type of information that an encoder needs to produce and write to an MPEG compliant bitstream, as well as the way in which the decoder needs to parse, decompress, and resynthesize this information to regain the encoded signals.[Q1] Other coding standards include, for example, ITU-T Recommendation H.263 “Video Coding for Low Bitrate Communication”, H.264, etc.
A typical video processing system 100 is illustrated in FIG. 1 which includes a video encoder 110 and a video decoder 130. In this configuration, the video encoder 110 and the video decoder 130 may operate in accordance with an established standard or specification. For example, the video encoder 110 and the video decoder 130 may operate in accordance with the MPEG-4 standard. Thus, the video encoder 110 may be referred to as MPEG-4 encoder and the video decoder 130 may be referred to as MPEG-4 decoder, respectively. In the system configuration illustrated in FIG. 1, at the transmitting end, the video encoder 110 receives video input data and encodes the video input data to generate or produce encoded video data that are transmitted to the video decoder 130 via a channel 120. The channel 120 can be a wireless or wired channel and is also referred to as the main channel or main stream herein. At the receiving end, the video decoder 130 receives the encoded video data, decodes the encoded video data to generate or produce video output data. During the transmission process over the channel 120, errors may be introduced due to various factors including noise, signal interference, fading, loss of connection, etc. Such errors will negatively impact the performance of the video decoder 130 and thus the quality of the video output data is degraded. Various conventional error coding techniques such as error detection coding, forward error correction (FEC), or automatic repeat/retransmission request (ARQ) schemes may be used to keep the error rate at an acceptable level. However, such conventional techniques may result in significant inefficiency because of the data redundancy and/or longer latency. Video compression standards also provide additional mechanisms to mitigate the adverse effects of errors introduced by transmission. These are resynchronization markers, data partitioning, reversible variable length coding (RVLC), etc. These error resilience tools increase the complexity of the encoder/decoder and increase the data rate required to transmit video information. Furthermore, these tools may not provide adequate protection against bursty errors typically seen in a spread spectrum communication channel such as a CDMA network.
Accordingly, there exists a need for a method, apparatus, and system for improving the quality of multimedia information such as video data in multimedia processing systems without incurring significant processing inefficiency.